As per the report submitted by Dzongkhag livestock office, Samtse, Bhutan, 86 poultry died between 12th August and 17th August 2010 in a semi-commercial farm belonging to Mr. Padam Gautam, Yodseltse geog in Samtse.
Initially seven deaths were observed on the night of 12th August; however, the owner did not report the matter to the concern authorities. On 15th August 2010, further 11 birds died in the farm, which came to the notice of Dzongkhag officials who visited the farm to buy eggs. These officials informally informed the Livestock Extension Centre in Yodseltse and subsequently the matter was reported to Dzongkhag Livestock Office in Samtse.
Detail investigation was then carried out by Dzongkhag Livestock staff in Samtse on 15th August and 17th August 2010. By then, 86 deaths have occurred at the farm. Rapid test for bird flu was carried out in the farm itself which gave a negative result indicating that these deaths were not related to Bird flu. A detail post-mortem was then carried out during the investigation and samples were submitted to National Centre for Animal Health (NCAH) for confirmation of the disease in the farm. Temporary control measures such as isolation of the affected flocks, bio-security and restriction of movement of people from the farm was advised and instituted.
Infectious Bursal Disease
On the evening of 19th August 2010, the National Centre for Animal Health received the samples for further processing. The samples were tested using real time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) on 20th August 2010 at NCAH in Serbithang for range of poultry diseases. The disease was confirmed as Infectious Bursal Disease (Gumboro Disease). The disease is difficult to diagnose in the field since the clinical signs are difficult to differentiate with Newcastle Disease. Based on the preliminary investigation the disease was reflected in the media as Newcastle Disease. With the availability of advance diagnostic techniques (rRT-PCR) at NCAH the disease is now confirmed as Infectious Bursal Disease.
Infectious Bursal Disease (Gumboro) is a viral disease of chicken occasionally reported from poultry farms around Bhutan. The disease was first noticed in early nineties and is most common in young poultry birds; however severe infection can also occur up to 18 weeks in some particular breeds of poultry birds. The disease is very mild in ducks. Affected poultry birds are depressed and show recumbency, ruffled plumage and white diarrhoea. The disease spreads rapidly within the flock and in susceptible birds death may occur as high as 60%.
Prevention of the Infectious Bursal disease is done through vaccination. The Department of Livestock regularly advocates vaccination for such diseases and the vaccines are supplied through NCAH, Serbithang. However the vaccines has to be procured by the farm owners at their own cost. Vaccines are administered at one week to 10 days age, followed by booster vaccination at 3-4th week in broilers and re-vaccination at 10-12 weeks, 18-20 weeks & 40 weeks for layers.
As per the report, the birds were not vaccinated against Infectious Bursal disease; therefore, negligence of the farm owner was the cause of the disease outbreak. Nevertheless, with the strict implementation of the control measures such as bio-security, isolation of the affected flocks and hygienic measures disease is now fully contained.
This disease does not have any public health implications.